Power supplies are well known and employed generally to provide one or more power supply voltages to an electrical device. In some applications, it may be advantageous to be able to adjust a power supply voltage.
For example, one technique, commonly referred to as margining, adjusts the power supply voltage of a power supply to an upper limit and/or a lower limit of an operational range of a system (e.g., the power supply and an electrical device supplied by the power supply). Margining is typically employed to verify the integrity and the reliability of the system. Another technique, commonly referred to as trimming, involves measuring the power supply voltage and adjusting the power supply voltage up or down to compensate, for example, for errors in the power supply or losses (e.g., line losses) associated with the delivery of the power to a load.
One type or class of power supply may be referred to as a voltage regulator module (VRM) power supply or VRM-style power supply. For example, an exemplary VRM power supply system 100, as illustrated in FIG. 1, supplies power 108 (labeled load power) to a load 104 (e.g., an integrated circuit or any type of electrical device). A voltage level associated with power 108 supplied to load 104 is based on a digital code 110 (referred to as a voltage identification, voltage ID, or VID) provided by load 104 to a VRM power supply 102 (labeled VRM). Digital code 110 (labeled VID) provides information to VRM power supply 102 as to a voltage level required by load 104 to operate properly.
One drawback of a conventional VRM power supply system is that a voltage level supplied by the VRM power supply is controlled solely by the digital code provided by the load. Consequently, there is generally no way to adjust the voltage level (e.g., via margining or trimming) provided by the VRM power supply, such as for example to test or account for losses or other characteristics of the system. As a result, there is a need for improved techniques for VRM power supply systems.